Chrysler Caravan/Voyager/Town n Country 1984-1995

Bendix Anti-lock 4 System Bleeding

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BLEEDING PROCEDURE



Modulator
  1. Assemble and install all brake system components on the vehicle, making sure all hydraulic fluid lines are installed and properly tightened.
  2.  
  3. Bleed the base brake system, using ONLY the bleeding procedure outlined in this section.
  4.  
  5. To perform the bleeding procedure on the ABS modulator assembly, the battery, battery tray and acid shield must be removed from vehicle. Then reconnect the vehicle's battery to vehicle's battery cables, using ONLY approved battery jumper cables.
  6.  
  7. Connect the DRB Diagnostics Tester to the vehicle's diagnostics connector. The vehicle diagnostic connector is located behind the fuse panel access cover on the lower section of the dash panel left of the steering column. The diagnostic connector is a blue 6 way connector.
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  9. Using the DRB check to make sure the CAB does not have any stored fault codes. If it does, remove them using the DRB..
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WARNING
When bleeding the modulator assembly wear safety glasses. A clear bleed tube must be attached to the modulator bleed screws and submerged in a clear container filled part way with fresh clean brake fluid. Direct the flow of brake fluid away from the painted surfaces of the vehicle. Brake fluid at high pressure may come out of the bleeder screws, when opened.

  1. When bleeding Anti-lock modulator assembly, the following bleeding sequence MUST be followed to insure a complete bleeding of all air from the Anti-lock brake, and base brake hydraulic systems. The modulator assembly can ONLY be bled using a manual bleeding procedure to pressurize the hydraulic system.
  2.  

Modulator Assembly Circuit

Bleed the circuits only in the following sequence: modulator primary check valve circuit, modulator secondary check valve circuit, modulator assembly primary sump circuit, modulator assembly primary accumulator circuit, modulator assembly secondary sump circuit, then the modulator assembly secondary accumulator circuit.

MODULATOR PRIMARY CHECK VALVE CIRCUIT

See Figure 1



Click image to see an enlarged view

Fig. Fig. 1: Bleeding the modulator assembly primary check valve circuit

To bleed hydraulic circuits of the Bendix Anti-lock 4 Brake System modulator assembly, the aid of a second mechanic or helper will be required to pump the brake pedal.

  1. Install a clear bleed tube on the primary check valve circuit bleed screw. Then insert the bleed tube into a clear container partially filled with fresh clean brake fluid.
  2.  
  3. Pump brake pedal several times, then apply and hold a constant medium to heavy force on brake pedal.
  4.  
  5. Open primary check valve circuit bleed screw at least 1 full turn to ensure an adequate flow of brake fluid. Continue bleeding primary check valve circuit until brake pedal bottoms.
  6.  
  7. After brake pedal bottoms, close, then tighten bleed screw. Release the brake pedal. Do not release the brake pedal prior to closing, then tightening the bleed screw.
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  9. Continue bleeding the modulator assembly, repeating Steps 2 through 4 until a clear, bubble free flow of brake fluid is evident.
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  11. When all air is bled from primary check valve circuit, tighten bleed screw and remove bleed hose from bleed screw. Do not remove bleed hose before tightening bleed screw, air may re-enter modulator.
  12.  
  13. Tighten modulator assembly primary bleed screw to 80 inch lbs. (9 Nm).
  14.  

MODULATOR SECONDARY CHECK VALVE CIRCUIT

See Figure 2



Click image to see an enlarged view

Fig. Fig. 2: Bleeding the modulator assembly secondary check valve circuit

  1. Move the clear bleed tube to the secondary check valve circuit bleed screw. Then insert the bleed tube into a container partially filled with fresh clean brake fluid.
  2.  
  3. Pump brake pedal several times, then apply and hold a constant medium to heavy force on brake pedal.
  4.  
  5. Open secondary check valve circuit bleeder screw, at least 1 full turn to ensure an adequate flow of brake fluid. Continue to bleed secondary check valve circuit until the brake pedal bottoms.
  6.  
  7. After brake pedal bottoms, close, then tighten bleed screw and release brake pedal. Do not release brake pedal prior to closing and tightening bleed screw.
  8.  
  9. Continue bleeding secondary check valve circuit, repeating Steps 2 through 4, until a clear, bubble free flow of brake fluid is evident.
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  11. When air is bled from primary check valve circuit, tighten bleed screw and remove bleed hose from bleed screw. Do not remove bleed hose before tightening bleed screw, air may re-enter modulator.
  12.  
  13. Tighten modulator assembly primary bleed screw to 80 inch lbs. (9 Nm).
  14.  

MODULATOR ASSEMBLY PRIMARY SUMP CIRCUIT

See Figure 3



Click image to see an enlarged view

Fig. Fig. 3: Bleeding the modulator assembly primary sump circuit

  1. Move clear bleed tube to primary sump bleed screw. Then install bleed tube into a container partially filled with fresh clean brake fluid.
  2.  
  3. Pump brake pedal several times, then apply and hold a constant medium to heavy force on brake pedal.
  4.  
  5. Open modulator assembly primary sump circuit bleed screw at least 1 full turn. This will ensure an adequate flow of brake fluid from the primary sump circuit.
  6.  
  7. Using the DRB, select the bleed ABS hydraulic unit mode. Then select the primary circuit. (The RF and LR solenoids will alternately fire for five seconds). Using the DRB, continue to select the primary circuit until an air-free flow of brake fluid from primary sump bleed screw is maintained or brake pedal bottoms. If an air-free flow is not maintained before brake pedal bottoms, close bleed screw and repeat Steps 2 to 4, until an air free flow is maintained.
  8.  
  9. After an air-free flow of brake fluid is maintained from primary sump bleed screw, close and lightly tighten bleeder screw. Then release brake pedal. Do not release brake pedal prior to closing and tightening bleeder screw.
  10.  
  11. After primary sump bleed screw is closed, remove bleed hose from primary sump bleed screw.
  12.  
  13. Tighten modulator assembly primary sump bleed screw to 80 inch lbs. (9 Nm).
  14.  

MODULATOR ASSEMBLY PRIMARY ACCUMULATOR CIRCUIT

See Figure 4



Click image to see an enlarged view

Fig. Fig. 4: Bleeding the modulator assembly primary accumulator circuit

  1. Transfer the clear bleed tube to the primary accumulator bleed screw. Then insert the bleed tube into a container partially filled with fresh clean brake fluid.
  2.  
  3. Pump brake pedal several times, then apply a constant medium to heavy force on the brake pedal. Using the DRB, select the bleed ABS hydraulic unit mode. Then select the primary circuit valves. (The RF and LR modulator assembly solenoids will fire for 5 seconds).
  4.  
  5. Open the modulator assembly primary accumulator circuit bleed screw at least one full turn. This will ensure an adequate flow of brake fluid from the primary accumulator circuit. Continue bleeding primary accumulator circuit until an air-free flow of brake fluid from bleed screw is maintained or the brake pedal bottoms. If an air-free flow of brake fluid is not maintained before brake pedal bottoms, close bleed screw and repeat Steps 1 and 2 until an air free flow is maintained.
  6.  
  7. After an air-free flow of brake fluid is maintained from the primary accumulator bleed screw, close and lightly tighten bleed screw. Then release pressure from brake pedal. Do not release force from brake pedal prior to closing and tightening bleed screw.
  8.  

For the next modulator assembly bleeding procedure, use of the DRB is not required. This step of the bleed procedure does not require modulator solenoids to be operated for bleeding to be performed.

  1. Pump brake pedal several times, then apply and hold a constant medium to heavy force on the brake pedal.
  2.  
  3. Again without firing modulator solenoids, open primary accumulator circuit bleed screw 1 full turn. This will ensure an adequate flow of brake fluid from the primary accumulator circuit.
  4.  
  5. Bleed primary accumulator circuit until a clear, air-free flow of brake fluid is maintained from the accumulator bleed screw or the brake pedal bottoms. If an air-free flow of brake fluid is not maintained from the bleed screw before the brake pedal bottoms. First, close bleed screw and then repeat Steps 4 and 5 of this bleeding procedure until an air-free flow is maintained.
  6.  
  7. After an air-free flow of brake fluid is maintained from the primary accumulator circuit bleed screw, close and lightly tighten bleed screw. Then release force from brake pedal. Do not release force from brake pedal prior to closing and tightening bleeder screw.
  8.  
  9. After primary accumulator bleed screw is closed, remove bleed hose from bleed screw.
  10.  
  11. Tighten primary accumulator bleed screw to 80 inch lbs. (9 Nm).
  12.  

MODULATOR ASSEMBLY SECONDARY SUMP CIRCUIT

See Figure 5



Click image to see an enlarged view

Fig. Fig. 5: Bleeding the modulator assembly secondary sump circuit

  1. Transfer the clear bleed tube to the secondary sump bleed screw on the modulator assembly. Then insert the bleed tube into a container partially filled with fresh clean brake fluid.
  2.  
  3. Pump brake pedal several times, then apply and hold a constant medium to heavy force on brake pedal.
  4.  
  5. Open the secondary sump circuit bleed screw at least 1 full turn. This will ensure an adequate flow of brake fluid is expelled from the secondary sump circuit.
  6.  
  7. Using the DRB, select the bleed ABS hydraulic unit mode. Then select the secondary circuit valves. (The LF and RR solenoids will alternately fire for five seconds). Continue bleeding secondary sump circuit until an air-free flow of brake fluid from secondary sump bleed screw is maintained or brake pedal bottoms. If an air-free flow of brake fluid is not maintained before brake pedal bottoms, close bleed screw and repeat Steps 2 through 4 until an air-free flow is maintained.
  8.  
  9. After an air-free flow of brake fluid is maintained from secondary sump bleed screw, close and lightly tighten bleed screw. Then release force from brake pedal. Do not release brake pedal prior to closing and tightening bleeder screw.
  10.  
  11. After secondary sump bleed screw is closed, remove bleed hose from bleed screw.
  12.  
  13. Tighten secondary sump bleed screw to 80 inch lbs. (9 Nm).
  14.  

MODULATOR ASSEMBLY SECONDARY ACCUMULATOR CIRCUIT

See Figure 6



Click image to see an enlarged view

Fig. Fig. 6: Bleeding the modulator assembly secondary accumulator circuit

  1. Transfer the bleed tube to the secondary accumulator bleed screw. Then insert the bleed tube into a container partially filled with fresh clean brake fluid.
  2.  
  3. Apply constant, medium to heavy force on the brake pedal.
  4.  
  5. Using the DRB, select the bleed ABS hydraulic unit mode,and then select the secondary circuit valves. (The LF and RR modulator assembly solenoids will fire for 5 seconds).
  6.  
  7. Open the secondary accumulator circuit bleed screw at least one full turn. This will ensure an adequate flow of brake fluid is expelled from the secondary accumulator circuit. Continue to bleed primary accumulator circuit, until an air-free flow of brake fluid from the bleed screw is maintained or brake pedal bottoms. If an air-free flow of brake fluid is not maintained from bleed screw before brake pedal bottoms, close bleed screw and then repeat Steps 1 and 2 until an air free flow is maintained.
  8.  
  9. After an air-free flow of brake fluid is maintained from the bleed screw, close and lightly tighten the bleed screw. Then release force from the brake pedal.
  10.  
  11. Do not release the force from brake pedal prior to closing and tightening the bleeder screw.
  12.  

For the next modulator assembly bleeding procedure, use of the DRB is not required. This step of the bleeding procedure does not require the modulator solenoids to be operated for bleeding to be performed.

  1. Pump the brake pedal several times, then apply and hold a constant medium to heavy force on the brake pedal.
  2.  
  3. Again without firing modulator assembly solenoids, open secondary accumulator circuit bleed screw at least 1 full turn. This will ensure an adequate flow of brake fluid is expelled from the secondary accumulator circuit.
  4.  
  5. Bleed secondary accumulator circuit until a clear, air-free flow of brake fluid is maintained from the secondary accumulator bleed screw or the brake pedal bottoms. If an air-free flow of brake fluid is not maintained from secondary accumulator bleed screw before brake pedal bottoms. Repeat Steps 5 and 6 of this bleeding procedure until an air-free flow is maintained from the bleeder screw.
  6.  
  7. After an air free flow of brake fluid is maintained from secondary accumulator circuit bleed screw, close and lightly tighten bleed screw. Then release force from brake pedal. Do not release force from brake pedal prior to closing and tightening bleed screw.
  8.  
  9. After secondary accumulator bleed screw is closed, remove bleed hose from bleed screw.
  10.  
  11. Tighten secondary accumulator bleed screw to 80 inch lbs. (9 Nm).
  12.  

 
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